"The scale and speed of reforms pose a significant risk to the future of the NHS in England."

Mr Lansley's controversial white paper potentially represents the biggest shake-up of the NHS in memory - despite the fact that its details weren't set out in either the Conservative manifesto or the coalition agreement.

The proposals mean the abolition of primary care trusts, with control over budgets placed in the hands of doctors.

Mr Lansley has argued that this represents a "liberating" decentralisation of power and saves the NHS huge costs in bureaucracy.

The reforms have hardly met with universal acclaim, with critics pointing out that they may leave health professionals with less time to actually treat patients.

More controversially, it is argued that the government lacks the mandate to push through such radical reforms, since it failed to appear in the prospectuses which the electorate voted on.

Dr Peter Carter, the RCN's general secretary, expressed some support for the principle of the decentralising agenda - but also deep concerns about the timing and scale of planned changes.

"The RCN welcomes the principles on which these reforms are based - putting patients at the heart of the NHS, focusing on outcomes and empowering clinicians", he said.

"However, they show a radical shift in the way health care is managed and provided, at a time when the NHS faces some of the biggest financial challenges of its history."